Agree on it looking like spider mites. The mites & their webbing will be much worse and more visible on the backs of the leaves. How much sun do they get? Here in Houston we're really hot, too, but we also have soupy humidity. In Dallas, you guys are generally a little hotter with drier air. With our continuous extreme heat that lasts as long as it does, if they are getting much sun, in the hottest parts of the year that can bleach them out and give them a case of sunburn even if they are generally sun lovers the rest of the year.
